[Morgagni-Adams-Stokes syndrome].
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Adams-Stokes Syndrome↗
Biomedical subjects
F Solti
Publications and source records attributed to F Solti.
Pacemaker therapy for the treatment of the long QT syndrome associated with long-lasting bradycardia and ventricular tachycardia. Electrophysiological characteristic and therapy.
The electrophysiological characteristics of the long QT syndrome (LQTS) associated with permanent bradycardia and ventricular tachycardiac attacks were electrophysiologically studied in 12 patients. Tachycardia could be induced by ventricular electrical stimulation in 11 cases. The following electrophysiological properties could be revealed: 1) a very short ventricular refractory period (VERP) compared with QT length; 2) inhomogeneity in VERP and QT interval in different areas of the ventricles; 3) repetitive ventricular responses on early ventricular electrical stimuli. Patients were successfully treated by pacemaker implantation and beta-blockers. In two patients a comparatively high pacing rate was required to reduce the QT interval.
Adult↗
The regulation of the cerebral circulation in long lasting bradycardia.
In the course of long lasting bradycardia in elderly patients, cardiac output will regularly diminish, circulation will slow down and signs of cerebral insufficiency may become manifest. The changes of cerebral circulation and its regulation were studied in 10 patients 61-74 years of age, with restricted cerebral regulatory capacity, suffering from permanent bradycardia. Cerebral blood flow was measured by using the venous isotope dilution technique by double punctures of the internal jugular vein. Hemispheric cerebral blood flow, cerebral O2 consumption and cerebral vascular resistance were determined during bradycardia and after termination of bradycardia by pacemaker. During long lasting bradycardia, cerebral blood flow and cerebral O2 consumption decreased, cerebral vascular resistance was elevated. After pacemaker implantation, cerebral blood flow and O2 consumption increased and cerebral vascular resistance decreased, approaching the normal value. The symptoms of cerebral insufficiency disappeared on improvement of the cerebral circulation.
Aged↗
Cerebral blood flow autoregulation during orthostatic manoeuvre in patients with permanent cardiac pacemaker.
Orthostatic test with passive tilting of the upper body was performed in 28 patients with VVI pacemaker. The changes in BP (Riva-Rocci method), CVR and CBF (impedance technique, REG II) as well as in EEG (automatic spectral analysis) observed after tilting, were compared to those in 20 age-matched controls. While in healthy subjects the autoregulation of the CBF was accomplished through a decrease in CVR and resulted in a moderate but significant increase in CBF, in patients the CVR did not change. This event was estimated as a sign of impaired autoregulation, the CBF remained unchanged most probably on account of the increased diastolic and mean BP. Alpha and beta power spectra in the EEG rose significantly after tilting, the shifts being more pronounced in the controls. In the patients there was an increase in theta activity. Cerebral angiopathy due to "subclinical" brain ischaemia during cardiac rhythm disorders preceding pacemaker implantation was accepted as a mechanism underlying the disturbed autoregulation of the cerebral blood flow. For the occurrence of alterations in orthostatic EEG reactivity, a dyscirculatory encephalopathy has been suspected.
Aged↗
Ultrastructural study of canine aortic damage caused by disturbance of transmural transport.
Lymph congestion was produced experimentally in canine aorta. It was demonstrated that the disturbance of lymph circulation resulted in morphological changes mostly in the outer third of the aortic media and in the adventitia. The smooth muscle cells of these areas showed mitochondrial or cytoplasmic edema and in the interstitium, ghost body formation could be seen, as well. The role of lymphatic circulation in the transmural transport of the aorta is stressed. The blocking of lymph drainage interferes with normal transmural transport and results in damages that contribute to the initiation of atherosclerotic lesions.
Animals↗
Effects of cardiac lymphostasis on sinus nodes. A histological study in canine experiment.
The mechanism of sinus node dysfunction caused by cardiac lymphostasis was studied in dogs with histological and electrophysiological methods. A total of seventeen mongrel dogs were used in this study. Out of them 12 animals were operated to induce cardiac lymphostasis and sacrificed 3, 6, and 10 days after operation. In 3 of the dogs, in addition to cardiac lymphostasis, local cardiac hypertension was induced by constricting the descending aorta (artificial coarctation of the aorta). The other five dogs were sacrificed as normal controls. The signs of deteriorated pacemaker function of the sinus nodes; sinus arrest escape rhythm, and bradycardia were observed in electrocardiographic (ECG) tracings in dogs with cardiac lymphostasis. The sinus node cells of the animals revealed cytoplasmic oedema, and swelling of the cells developed progressively parallel to the time elapsed after the operation. The pathological changes in the animals with combined lymphostasis and local hypertension were more severe than those seen in the animals with lymphostasis only. In one out of the three dogs with combined operation, scattered foci of necrobiotic sinus node cells and necrobiosis of the medial smooth muscle cells in sinus node arteries were also observed. It was concluded in the present study that cardiac lymphostasis induced water and electrolyte imbalance in sinus nodes. The disturbed water and electrolyte homeostasis resulted in alterations in the electrophysiological activity of the sinus nodes. In order to elucidate the exact relationship between cardiac lymphostasis and human sick sinus syndrome, further experimental and clinical studies will be necessary.
Animals↗
Arteriovenous shunt-circulation in lymphoedematous limbs.
In lymphoedema of the extremities arteriovenous shunt circulation develops. Regulation of limb circulation was studied in 28 cases of (primary and secondary) lymphoedema by using the venous isotope dilution method and technetium-macroaggregate perfusion scintigraphy. As a result of lymphoedema, limb circulation (total limb circulation) increases, arteriovenous O2 difference is low and the O2 uptake of the tissues is normal. The development of arteriovenous (micro-, and macro-) shunts can be directly visualized by perfusion scintigraphy. In lymphoedema of the extremities the nutritive--capillary--blood supply of the tissues remains normal and therefore, no trophic disturbances develop. Lymphoedema is often associated with a fairly considerable arteriovenous shunt circulation and, in such cases, the cardiac output as well as cardiac performance are enhanced.
Adult↗
Electrophysiological characteristics of lorcainide, a new antiarrhythmic drug.
The electrophysiological characteristics and the antiarrhythmic indication areas of lorcainide were studied by using electrophysiological investigations and clinical studies in patients suffering from sustained arrhythmias. According to the data of the arrhythmia analyses (30 patients) the most important electrophysiological effects of lorcainide are: increase of the effective refractory period of the atria and ventricles; prolongation of the conduction time in the His bundle; prolongation of the refractory period and conduction of the accessory pathways. In the course of clinical studies (55 patients) lorcainide proved to be very effective in treating ventricular arrhythmias and preventing or disrupting ventricular tachyarrhythmic attacks. Lorcainide has a very promising antiarrhythmic effect in the suppression of tachyarrhythmias with accessory pathway conduction, too.
Adolescent↗
CLS 2210, hyaluronidase and the cardiac lymphatic system.
Earlier studies have shown that hyaluronidase exerts a potent influence upon the lymphatic system of the myocardium and that it reduces the size of myocardial infarcts after coronary occlusion. In this study we compared, in mongrel dogs, the effect of intravenous hyaluronidase or CLS 2210 upon the cardiac lymphatic vessels. We observed that in CLS 2210-treated animals the number of visualized cardiac lymphatic vessels was significantly higher than in the hyaluronidase-treated control group. We have previously demonstrated a cardioprotective effect of hyaluronidase in the treatment of acute myocardial infarction. The present experimental data indicate that intravenous CLS 2210 may have a definite role in the management of acute coronary occlusion. Further studies are needed to confirm these preliminary findings.
Animals↗
Arteriovenous shunts in peripheral lymphedema: hemodynamic features and isotopic visualization.
The hemodynamic characteristics of peripheral lymphedema were studied in 28 patients with uni- or bilateral leg swelling. Leg blood flow was measured by venous isotope dilution (a technique for nutritive--capillary blood flow) and arteriovenous shunts were visualized by perfusion scintigraphy using radiolabelled macroaggregated albumin. Arteriovenous communications were uniformly detected in lymphedema, with a calculated "shunt flow" of 200 to 600 ml/min. Other features in the lymphedematous leg included an elevated limb blood flow rate and narrowed arteriovenous oxygen difference.
Albumins↗
Physiological and pharmacological analysis of transmembrane action potentials of human atrial fibers.
Transmembrane action potentials (APs) of electrically paced right-atrial tissue obtained from 38 patients of corrective open-heart surgery were analyzed. Two types of APs could be found. The APs of 20 patients (group I) were similar to those of other laboratory mammals. The average resting potential (RP) and the amplitude and maximum rate of rise of phase 0 of APs (Vmax) were -75 mV, 86 mV, and 152 V/sec, respectively, only the repolarization phase being more prolonged than that of other mammalian APs. Epinephrine (5.8 X 10(-6) mole/liter) increased the amplitude of APs and prolonged the plateau phase, producing odd-looking, humped APs. Prostacyclin-Na (6.7 X 10(-7) and 8.7 X 10(-6) mole/liter) increased Vmax. Celluline-A (a biological Ca-complex obtained from frog skin) increased both Vmax and the amplitude of APs and, similar to epinephrine, prolonged the plateau phase. In group I, postoperative arrhythmias occurred in only 1 of the 10 patients. APs obtained from another 18 preparations (group II) were characterized by low RP (-55 mV), small amplitude of AP (59 mV), slow rate of rise of AP (less than 10 V/sec), and very prolonged repolarization. This type of APs can be referred to as slow-response APs. Neither epinephrine, prostacylin-Na, nor celluline-A modified the characteristics of these slow-response APs. In group II, postoperative arrhythmias could be observed in 8 of the 10 patients.
Adolescent↗
Recording of sinus node electrogram: its technique, electrophysiological and clinical importance.
The electric sign of sinus node activity, the sinus node electrogram, was recorded in animal experiments and in 22 patients. In humans the electric sign of the sinus node precedes the atrial activation by 60 msec on the average. Atrial impulse conduction time is somewhat longer than the sinoauricular one. Canine sinus node electrogram is very similar to that recorded in humans but sinoauricular impulse conduction is somewhat quicker in dogs. The pathological importance of the sinus node electrogram is discussed.
Adult↗
Effect of acute cardiac lymph stasis on metabolic coronary adaptation in the dog.
Surgical blockade of cardiac lymph drainage was performed in dogs to examine the effect of acute cardiac lymph stasis on coronary adaptive mechanisms. Coronary blood flow (CBF) was measured using an electromagnetic flow probe on the left anterior descending (LAD) artery. Metabolic autoregulatory capacity was assessed by eliciting reactive hyperemic responses after flow interruptions of 10-60 second duration and by administering submaximal doses (250-500 micrograms) of adenosine, the putative transmitter of reactive hyperemia, into the left heart. The effect of lymph stasis was tested in two experimental groups, one hour and 48 hours after lymph obstruction and the data compared to control dogs. Although cardiac lymph stasis did not notably affect baseline arterial pressure and CBF, both reactive hyperemic response and adenosine-induced coronary vasodilation were reduced significantly (equal to or less than 50% control). On occasion, a complete absence of autoregulation was observed. These findings suggest that cardiac lymph stasis decreases vascular responsiveness to physiologic vasodilator stimuli and/or retards diffusion of biologically unstable substance(s) presumably involved in autoregulation. Persistently impaired coronary autoregulation in the lymphedematous heart may contribute to progressive ischemic damage as for example after myocardial infarction.
Adaptation, Physiological↗
[Advances and contradictions in pacemaker therapy of arrhythmias].
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Arrhythmias, Cardiac↗
Autonomic sinus node dysfunction and its treatment.
The clinical, electrocardiographic, pharmacologic, electrophysiologic and Holter monitoring findings are described in four patients with autonomic sinus node dysfunction and one patient with autonomic binodal disease. All showed cerebral symptoms, and had attacks of dizziness, weakness, near-syncope or syncope. After a pharmacologic autonomic blockade with propranolol and atropine, all patients had normal intrinsic heart rates. Electrophysiological studies revealed normal corrected intrinsic node recovery time (less than or equal to 240 msec) a gradual return to the basic cycle length in the secondary postpacing cycles after autonomic blockade, and no intrinsic paroxysmal atrioventricular block. Continuous ECG monitoring (1-3 X 24 hours) revealed severe sinus bradycardia, SA-block, severe sinus arrest, cardiac standstill, atrial fibrillation and in two patients associated AV-block. Autonomic blockade with electrophysiological studies exclude the intrinsic involvement of the sinoatrial and atrioventricular node. Holter monitoring is the best method for assessing the autonomic neurovegetative component of dysrhythmias. Therapy regarding isolated autonomic sinus node dysfunction depended on the pathomechanisms of rhythm disorders: two patients received permanent pacemakers, antiarrhythmic drugs were applied in the case of two patients, and etiological treatment in the case of one. During the follow-up, all patients became symptom-free.
Adult↗
The effect of adenosine on impulse formation and propagation in the heart. Electrophysiologic studies and clinical implications.
The effect of adenosine on impulse formation and conduction in the heart was studied in 20 dogs by the sinus node artery perfusion technique. Electrophysiologic studies were performed by using His electrograms and epicardial electrograms of the atria and left ventricle. This action potential was recorded in the hearts of 10 dogs. After adenosine administration, there first developed bradycardia, then sinus arrest. Instead of sinus rhythm, there appeared a junctional escape rhythm. Atrial extrasystoles could be also regularly detected. Impulse conduction slowed down in the AV node. Similar changes could be observed after local administration of verapamil. Adenosine decreased the resting membrane potential and the maximum rate of depolarisation in atrial tissue preparations. Experimental data support the assumption that slow Ca++ channels are involved in the bradycardiac effect of adenosine.
Adenosine↗
The electrophysiological peculiarities of childhood tachyarrhythmias.
Electrophysiological analysis of 20 patients in child or adolescent age affected by paroxysmal tachycardia has been performed. In 16 cases the tachycardia was supraventricular and in 4 cases it was ventricular. Evaluation of the electrophysiological parameters revealed certain characteristics of childhood tachyarrhythmias, viz. (1) adequate sinus node function, absence of sinus dysfunction, (2) absence of brachycardia, (3) acceleration of anterograde and retrograde atrioventricular impulse conduction systems.
Adolescent↗
[Pacemaker implantation in a 100-year-old patient].
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Age Factors↗